By Keith Coffman and Rich McKay DENVER (Reuters) – A sizzling heat wave will blanket a wide swath of the Eastern United States this weekend, pushing temperatures in New York and Boston to near record highs, while Denver is bracing for a foot or more of snow, the National Weather Service said on Friday. From Washington, D.C. to Massachusetts, forecasters say the mercury could reach in the mid-to-upper 90s. Normally at this time of year, the region enjoys cool springtime weather in the upper 60s to mid 70s, said Marc Chenard, a forecaster with the NWS Weather Prediction Center in College Park, M…